1. Field of the Invention
This invention relates to a channel assigning system for use in an electronic musical instrument, and more particularly, to an improved system for assigning channels to musical tones of individual musical-tone parts (hereunder referred to simply as parts) of a piece of music to be performed.
2. Description of the Related Art
Recently, electronic musical instruments adapted to simultaneously output musical tones of different parts (e.g., musical tones having different timbres) where a plurality of musical tones are simultaneously sounded have been proposed. One example of such a conventional electronic musical instrument is the type which outputs musical tones having a plurality of timbres, at the same time, and another example of these conventional electronic musical instruments i.e the type which inputs information about musical tones having different timbres from other electronic musical instruments, similar the operation of a Musical Instrument Digital Interface (MIDI) system.
Where a channel is assigned to musical tones of each of the parts in this type of conventional electronic musical instrument, the number of channels to be assigned to each of the parts is fixed. This prevents the number of sounded musical tones of one part, in which few "key on" and "key off" events occur, from utilizing fewer channels. than a sounded musical tones of another part in which a relatively large number of "key on" and "key off" events occur. Note, a "key on" event is an occurrence of the operation of turning on (or depressing), for example, a key corresponding to a musical tone of a part of a piece of music to be played. Conversely, a "key off" event is an occurrence of the operation of turning off (or releasing) a key corresponding to a musical tone of the part of the piece of music.
Nevertheless, as a result of fixing the number of channels to be assigned to each part, when a channel is assigned to a part, and the performance of that part is interrupted, the assigned channel is not used at all (i.e., is wasted), in this conventional electronic musical instrument, during the interruption of the performance of the part.
Conversely, in the case of another conventional electronic musical instrument, a channel is assigned regardless of which part the "key on" event for a musical tone occurred. Although this eliminates the unused (i.e., wasted) channels, this conventional electronic musical instrument cannot prevent the number of sounded musical tones of a part in which few "key on" and "key off" events occur from becoming much less than that of sounded musical tones of another part in which a relatively large number of "key on" and "key off" events occur.
The present invention has been created in order to solve the above described problems of the conventional electronic musical instruments.
Therefore, an object of the present invention is to provide a channel assigning system for use in an electronic musical instrument, by which a predetermined number of simultaneously sounded musical tones of each part can be secured and musical tones in a number greater than the predetermined number can be sounded, to thereby ensure an efficient use of the channels.